WO2008047435A1

WO2008047435A1 - Insulator

Info

Publication number: WO2008047435A1
Application number: PCT/JP2006/320839
Authority: WO
Inventors: Shinichi Wada; Nobuo Ogura
Original assignee: Husqvarna Zenoah Co.,Ltd.
Priority date: 2006-10-19
Filing date: 2006-10-19
Publication date: 2008-04-24
Also published as: CN101529074A; DE112006004084T5; US20100294249A1

Abstract

An insulator (30) in which an acceleration pump fixing portion (51) is provided at the lower part of a heat insulating section (31), and an acceleration pump (50) is fixed to the acceleration pump fixing portion (51). A passage (41) is formed at the lower part of a heat insulating section (31), a groove (42) connecting an insulator air passage (32) with the passage (41) is formed in the connection surface (43) with an engine (1), and a passage (61) connecting the passage (41) with a negative pressure introduction chamber (70) is provided at the upper part of the acceleration pump (50). Consequently, the acceleration pump (50) can be easilyarranged in a space under the insulator (30), which has been essentially a dead space, and, since external piping for allowing communication between the insulator (30) and the acceleration pump (50) can be eliminated, space saving can be achieved and the communication structure can be simplified.

Description

Specification

Insulator Technical Field

TECHNICAL FIELD [0001] The present invention relates to an engine insulator, and for example, relates to an insulator used in a stratified scavenging two-cycle engine.

Background art

[0002] In a two-cycle engine, an exhaust port and a scavenging port are opened and closed by a piston. When the exhaust port is opened by lowering the piston, the combustion gas is discharged as exhaust gas, and the air-fuel mixture in the crank chamber flows into the cylinder through the scavenging passage from the scavenging port that is opened almost simultaneously. The air-fuel mixture that has flowed in will flow out, albeit slightly, while scavenging the combustion gas remaining in the cylinder before the piston closes the exhaust port. Therefore, although unsatisfactory, unburned fuel in the air-fuel mixture will be discharged together with the exhaust gas, leading to a reduction in fuel consumption due to fuel loss and a potential for environmental conservation. is there. For this reason, a complicated muffler structure was required to separate the exhaust gas power unburned fuel and prevent it from going outside.

In order to solve this problem, a stratified scavenging two-cycle engine has been proposed. The stratified scavenging two-cycle engine has an air passage communicating with the scavenging passage. Thus, air can be supplied to the upper side in the scavenging passage prior to scavenging by the air-fuel mixture. During scavenging, this air is first introduced into the cylinder, and the mixture continues later. This makes it difficult for the air-fuel mixture to flow out to the exhaust port, improving fuel efficiency and eliminating the need for a complicated muffler structure.

[0004] On the other hand, not only a stratified scavenging two-cycle engine but also an ordinary engine generally operates idling in a lean mixture state. However, in the case of a stratified scavenging two-cycle engine, if the idling state force sudden acceleration is performed, the air with the air passage force is supplied into the cylinder first, so that the mixture with a predetermined fuel ratio that follows later is sufficient. It is not supplied, and the lean mixed vaporization progresses further, resulting in poor acceleration or engine stoppage. As a countermeasure technology, an acceleration device that temporarily increases the fuel amount during acceleration is installed. (For example, Patent Document 1).

[0005] The acceleration device of Patent Document 1 includes a carburetor, an insulator provided between the carburetor and the engine to suppress heat transfer from the engine, and an acceleration pump connected to the carburetor, and an air passage of the insulator. And the acceleration pump are connected by piping.

[0006] Patent Document 1: JP 2001-123841 (pages 2-4)

Disclosure of the invention

Problems to be solved by the invention

[0007] However, in the acceleration device described in Patent Document 1, the acceleration pump force insulator is provided away from the carburetor! Therefore, it is necessary to secure an installation space for the acceleration pump separately from the insulator and the carburetor. There is a problem that there is. In addition, since the acceleration pump and the insulator are connected by piping, there is a problem that the communication structure by the piping becomes complicated when the acceleration pump is arranged at a position far away from the insulator.

[0008] An object of the present invention is to provide an insulator capable of simplifying the communication structure and realizing space saving around the engine.

Means for solving the problem

[0009] An insulator according to the present invention is provided between an engine and a carburetor and has an insulator air passage and an insulator mixture passage, and is formed integrally with the heat insulator, and an acceleration pump is attached to the insulator. And an accelerating pump mounting portion.

[0010] According to the present invention, the acceleration pump mounting portion is provided integrally with the heat insulating portion. Therefore, by installing the acceleration pump to the acceleration pump mounting portion, the acceleration is accelerated around the insulator that has conventionally been a dead space. The pump can be arranged well, and it is not necessary to provide a separate installation space exclusively for the acceleration pump, thus saving space. Even when piping is used to connect the air passage of the insulator and the negative pressure introduction chamber, the accelerating pump can be installed directly around the heat insulation, so the length of the piping is very short. Easy to do. [0011] In the insulator according to the present invention, a negative pressure introduction chamber of an acceleration pump attached to the acceleration pump attachment portion and an insulator air passage of the heat insulation portion on a connection surface of the heat insulation portion with the engine or the carburetor. It is preferable to form a groove for the pressure introduction passage that communicates with! / ,!

[0012] According to the present invention, the insulator air passage and the negative pressure introduction chamber communicate with each other through the pressure introduction passage formed therein, and the pressure introduction passage forms a groove on the connection surface with the engine or the carburetor. Since it is formed in such a way, conventional external piping can be eliminated, and the communication structure can be further simplified. In addition, such a groove is blocked by the connection surface of the engine or the carburetor and becomes tubular.

Brief Description of Drawings

FIG. 1 is a side sectional view showing a structure around an insulator according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the insulator.

FIG. 3 is a rear view of the insulator.

FIG. 4 is a side sectional view showing a part of the structure around an insulator according to a second embodiment of the present invention with a part omitted.

FIG. 5 is a side cross-sectional view showing a portion of the structure around an insulator according to a third embodiment of the present invention with a part omitted.

Explanation of symbols

[0014] 1 ··· Engine, 20 ··· Cabretta, 30 ··· Insulator, 31 ··· Insulation, 32 ··· Insulator air passage, 33 ··· Insulator mixed air passage, 41 ··· · Passage, 42 · · · Groove, 50 · · · Acceleration pump, 51 · · · Acceleration pump mounting portion, 61 · · · Connection passage, 80 · · · Pressure introduction passage.

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment]

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a side sectional view showing the structure around the insulator 30 according to the present embodiment, FIG. 2 is an exploded perspective view of the insulator 30, and FIG. 3 is a rear view of the insulator 30.

A stratified scavenging two-cycle engine 1 is provided with an insulator 30 according to the present invention, and includes an air passage 2 and an air-fuel mixture passage 3 provided on the intake side (see FIG. 3). In the entrance stroke, scavenging air and air-fuel mixture are sucked through the passages 2 and 3. As shown in FIG. 1, a carburetor 20 is attached to such an engine 1 via an insulator 30, and an air cleaner 10 containing a filter element (not shown) is attached to the carburetor 20.

The air cleaner 10 is provided with an air inlet 11, and a lower part of the air inlet 11 is provided with a soot inlet 12. A grommet 13 is attached to the gutter inlet 12, and a protrusion 25 protruding from the carburetor 20 is inserted into the grommet 13. The scavenging air sent to the engine 1 and the air that is the basis of the mixture are first sucked from the intake port 11 and sent to the carburetor 20.

[0018] The carburetor 20 has a cab air passage 21 on the upper side, a cab mixture passage 22 on the lower side, and a constant pressure fuel supply mechanism at the bottom. The constant pressure fuel supply mechanism includes a constant pressure fuel chamber partitioned on the upper side across a first film (not shown) and a carburetor constant pressure chamber 24 partitioned on the lower side. The carburetor constant pressure chamber 24 communicates with the air cleaner 10 side (atmosphere side) through a communication passage 250 provided inside the protrusion 25, and the constant pressure fuel chamber communicates with the cab mixture passage 22. A fuel pump or the like is formed on the upper part of the constant pressure fuel chamber by the second membrane. The second membrane moves up and down by the pulsation pressure of the crank chamber transmitted from the engine 1, so that the fuel in the fuel tank is supplied to the constant pressure fuel chamber.

During normal operation of the engine 1, the fuel in the constant pressure fuel chamber is sucked out into the constant pressure fuel chamber force / cavity passage 22 by the negative pressure generated in the cap mixture passage 22. Part of the air sucked from the intake port 11 flows into the cap air passage 21 and is sent to the insulator 30, and the remaining air flows into the cap mixture passage 22 and then sucked out of the constant pressure fuel chamber. It is mixed with fuel and sent to the insulator 30 as an air-fuel mixture.

[0020] The insulator 30 is a synthetic resin member that suppresses heat transfer from the engine 1 to the carburetor 20. In this embodiment, the insulator 30 is provided below the heat insulating portion 31 and the heat insulating portion 31 for suppressing heat transfer. A frame-shaped acceleration pump mounting portion 51 to which the acceleration pump 50 is mounted is integrally provided. In other words, in this embodiment, the acceleration pump 50 is attached to such an acceleration pump mounting portion 51, so that the acceleration is performed under the heat insulating portion 31 and in the space between the engine 1 and the carburetor 20. The pump 50 is arranged, and this space has been a dead space where nothing is arranged. For this reason, in this embodiment, such dead space is used. If the acceleration pump 50 is provided by effectively using the source, space can be saved.

[0021] The heat insulating section 31 includes an insulator air passage 32 that connects the cab air passage 21 and the air passage 2 on the engine 1 side, and an insulator that connects the cap mixture passage 22 and the mixture passage 3 on the engine 1 side. A mixture passage 33 is provided, and a pulsation transmission passage 34 is provided below the insulator mixture passage 33. One end of the pulsation transmission passage 34 communicates with the crank chamber of the engine 1, and the other end communicates with the constant pressure fuel supply mechanism to transmit the pulsation pressure in the crank chamber to the constant pressure fuel supply mechanism. In addition, the heat insulating portion 31 is provided with a pair of connecting holes 35. A nut 36 is embedded in the back side of the connecting hole 35. A screw (not shown) that passes through the air cleaner 10 and the carburetor 20 is inserted into the connecting hole 35, and the air cleaner 10 and the carburetor 20 are attached to the insulator 30 by screwing the screw into the nut 36.

[0022] Further, the heat insulating portion 31 is provided with a passage 41 that penetrates the lower side in the lateral direction (left-right direction in FIG. 1). A groove 42 connecting the insulator air passage 32 and the passage 41 is formed in the connection surface 43 of the heat insulating portion 31 with the engine 1.

As shown in FIG. 2, the acceleration pump 50 includes a plate 52 mounted on the engine 1 side of the acceleration pump mounting portion 51, and a first case 55 mounted on the carburetor 20 side of the acceleration pump mounting portion 51. And a second case 58 covering the first case 55, and these are assembled together by a screw 64. Further, a gasket 53 is interposed between the acceleration pump mounting portion 51 and the first case 55, and a diaphragm 56 and a gasket 57 are interposed between the first case 55 and the second case 58. . Further, the first case 55 is provided with a support wall 54, and a spring 59 is disposed between the support wall 54 and the diaphragm 56.

[0024] The space defined by the acceleration pump mounting portion 51, the plate 52, the gasket 53, and the support wall 54 of the first case 55 is defined as the negative pressure introduction chamber 70, and the support wall 54 and the diamond of the first case 55 A space defined by the diaphragm 56 is a negative pressure chamber 71, and a space defined by the diaphragm 56, the gasket 57, and the second case 58 is a pump chamber 72. Further, the negative pressure introducing chamber 70 and the negative pressure chamber 71 communicate with each other through the communication hole 73. That is, the acceleration pump mounting portion 51 in this embodiment forms a negative pressure introduction chamber 70 of the acceleration pump 50! /, And! /, And constitutes a part of the acceleration pump 50. . [0025] At the upper part of the first case, a connection portion 60 is provided at a position where it does not interfere with the pulsation transmission passage 34. The connection portion 60 protrudes upward from the first case 55 and is provided so as to contact the vicinity of the passage 41 provided in the lower portion of the heat insulating portion 31. The connecting portion 60 is provided with a groove-like connecting passage 61 that connects the passage 41 of the heat insulating portion 31 and the negative pressure introducing chamber 70 in communication. The second case 58 is provided with a ridge entrance 62. A grommet 63 is attached to the gutter inlet 62, and a protrusion 23 projecting from the carburetor 20 is inserted into the grommet 63. The pump chamber 72 communicates with the carburetor constant pressure chamber 24 through a communication passage 230 provided inside the protrusion 23.

[0026] In such a heat insulating portion 31 and the acceleration pump 50, a groove 42 provided in the connection surface 43 of the heat insulating portion 31 is closed by the force 42 engine 1 to form a tubular shape. Since the connection passage 61 provided in the case is also blocked by the side surface of the acceleration pump mounting portion 51 and becomes tubular, the insulator air passage 32 and the negative pressure introduction chamber 70 are connected in communication, and the negative pressure of the insulator air passage 32 is reduced. It is introduced into the negative pressure introducing chamber 70 and eventually into the negative pressure chamber 71. Therefore, there is no need for external piping for connecting the insulator and the acceleration pump as in the conventional case, the communication structure can be simplified, and the assembly can be facilitated. The groove 42, the passage 41, and the connection passage 61 constitute a pressure introduction passage 80 according to the present invention.

[0027] Further, the above-described carburetor 20 and the insulator 30 operate as follows.

First, during idling, the cap air passage 21 is closed in conjunction with the throttle valve in the cap mixture passage 22, so that the air passages 2, 21, and 32 are at negative pressure. For this reason, negative pressure is introduced into the negative pressure introduction chamber 70 from the insulator air passage 32 through the pressure introduction passage 80, and the diaphragm 56 is piled on the spring force of the spring 59 and pulled toward the negative pressure chamber 71. As a result, the throttle valve opens when the engine 1 accelerates, and in conjunction with this, the insulator air passage 32 is also opened and the negative pressure disappears all at once.

As a result, the diaphragm 56 is instantaneously returned to the pump chamber 72 side by the spring force of the panel 59, and the air in the pump chamber 72 is pressure-fed to the carburetor constant pressure chamber 24 through the communication path 230. For this purpose, the first membrane that separates the constant pressure fuel chamber and the carburetor constant pressure chamber 24 is pushed up, and the fuel in the constant pressure fuel chamber is pressurized, so that the amount of fuel supplied to the cap mixture passage 22 is reduced. To increase. Therefore, during sudden acceleration, the fuel supply amount is temporarily increased by the acceleration pump 50, so that the engine 1 can be smoothly accelerated even during sudden acceleration. At this time, the inner diameter of the communication path 250 connected to the constant pressure chamber 24 is smaller than the inner diameter of the communication path 230 from the acceleration pump 50 side. It is possible to push up the membrane of 1 reliably.

[Second Embodiment]

In FIG. 4, a side sectional view showing the structure around the insulator 30 according to the second embodiment of the present invention is partially omitted. In this embodiment, the same members and the same functional parts as those in the first embodiment described above are denoted by the same reference numerals, and description thereof will be omitted or simplified here. The same applies to the third embodiment described below.

[0030] Unlike the first embodiment described above, the present embodiment is characterized in that the acceleration pump mounting portion 51 constitutes a part of the calo speed pump 50.

The acceleration pump mounting portion 51 is provided so as to protrude below the heat insulating portion 31 so that the acceleration pump 50 can be mounted by a screw or the like. At this time, the passage 41 is provided in the lower part of the heat insulating portion 31, passes through the acceleration pump mounting portion 51, and is connected to the connection passage 61 provided in the acceleration pump 50.

In this embodiment as well, the acceleration pump mounting portion 51 is provided integrally with the heat insulating portion 31, and the acceleration pump 50 is mounted on the acceleration pump mounting portion 51. Therefore, the acceleration pump 50 is disposed below the heat insulating portion 31, and the pressure introduction passage 80 connects the insulator air passage 32 and the negative pressure introduction chamber 70 in communication with each other. The same operational effects as in the first embodiment can be obtained, the installation space for the acceleration pump and the external piping are not required, space saving can be realized, and the communication structure can be simplified.

In particular, in the present embodiment, the acceleration pump mounting portion 51 constitutes a part of the acceleration pump 50, so that the structure of the insulator 30 can be simplified.

[Third Embodiment]

FIG. 5 shows a third embodiment of the present invention.

In this embodiment, the acceleration pump mounting part 51 is provided in the front and rear of the lower part of the heat insulating part 31 (both sides in the left and right direction in FIG. 5), and does not constitute a part of the acceleration pump 50. The provided passage 41 is characterized in that it does not pass through the acceleration pump mounting portion 51 but is connected to the connection passage 61 in the connection portion 60 provided in the acceleration pump 50.

In this embodiment as well, the same effect can be obtained with the same configuration as the first and second embodiments described above.

It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.

For example, the groove 42 of the insulator 30 may be formed on the connection surface of the heat insulating portion 31 with the carburetor 20 to constitute the pressure introduction passage 80.

Further, the insulator air passage 32 and the negative pressure introduction chamber 70 may be communicated with each other by pipes, not necessarily through the pressure introduction passage 80 formed including the groove 42. Even in this case, the accelerating pump 50 is arranged at a position close to the periphery of the heat insulating portion 31, so that the communication structure can be simplified because the length of the pipe is very short.

Industrial applicability

[0034] The present invention can be used in portable work machines such as blowers and brush cutters as an accelerator-integrated insulator provided between a stratified scavenging two-cycle engine and a carburetor.

Claims

The scope of the claims

[1] A heat insulating portion provided between the engine and the carburetor and having an insulator air passage and an insulator mixture passage,

An acceleration pump mounting portion that is integrally formed with the heat insulating portion and to which the acceleration pump is mounted.

An insulator characterized by that.

[2] In the insulator according to claim 1,

A connecting surface of the heat insulating portion with the engine or the carburetor is used for a pressure introducing passage for communicating a negative pressure introducing chamber of an acceleration pump attached to the acceleration pump attaching portion and an insulator air passage of the heat insulating portion. Grooves are formed

An insulator characterized by that.